[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: Is Elisp really that slow?

From: Emanuel Berg
Subject: Re: Is Elisp really that slow?
Date: Wed, 15 May 2019 13:25:25 +0200
User-agent: Gnus/5.13 (Gnus v5.13) Emacs/25.1 (gnu/linux)

tomas wrote:

>>>> 1) Identify what is slow in Elisp.
>>>> 2) Rewrite it in C?
>>> 3) Write a regexp-to-assembler compiler.
>>>    Bonus points if that runs on the GPU,
>>>    using its SIMD features.
>> Please DIY Mr. Zerolo, personally I'd be
>> happy to try out translating Elisp into C.
> But regexp match /was/ the bottleneck in the
> code sample you posted, whose core loop is:
>   (while (re-search-forward regexp end t)
>           (replace-match to-string) )
> (go benchmark it, Emacs offers great
> facilities for that). So no amount of Elisp
> -> C translation or other Elisp speedup will
> make your code noticeably faster.

:) I believe you! It is not that. Personally,
I don't really care that much for Emacs' speed.
I don't really care if other people use it or
not [1]. I mean, I'd _like_ it to be faster and for
more people to use it. But it doesn't bug me on
a daily basis, if you get me.

So from a personal POV, I would be
interesting/fun to write some of my Elisp into
C, and if I get good enough at it, maybe
I could even do it for the project.

You know my Elisp, hardly brilliant but
capable, and I think my C would be good again
if I picked it up after not doing it for
many years.

So the practical issue is how to do it not in
the Elisp sense, not in the C sense, but in the
_Elisp-to-C sense in the context of Emacs_.
And for that purpose, the Elisp I posted and
you referred to (thank you) is too complicated!
Baby steps first.

So, how do I write this in C with correct

(defun hello-elisp-world ()
  "This docstring is for display purposes only."
  (message "hello Elisp world!")
;; (hello-elisp-world) ; eval me, otherwise you don't know what it does

Them, where do I put it (assuming it gets its
own file for test purposes) and do I need to
change the Makefile or build process in general
to make it work?

> Notice how this ‘C source code’ above is
> a link? Follow it, either by putting point on
> it and hitting ENTER or by mouse- clicking on
> it, and presto, you are in the middle of
> a C function written to be called from Elisp

Yes, I know about that, of course :) I think
you suspected that, but thanks anyway as I'm
not the only one reading this...

> (you compile your Emacs from source code, do
> you?).

I don't because I didn't get Emacs-w3m to work
last time I tried, and I always prefered the
repos, anyway. But installation of Emacs itself
was amazingly smooth. I solved the problem with
Emacs-w3m with "apt pinning", which I described
here: [2]

If your comment refers to the Emacs C source,
one can set that up even tho one has Emacs from
the repos. Apparently now it isn't for me, as
it doesn't work, but I have done it before, so
I know it's possible :) If your comment refers
to ~"make a manual install and start mucking
around", I can do that as well :)

> In the manual, there is "E7. Writing Emacs
> Primitives".

You mean this one:

    (info "(elisp) Writing Emacs Primitives")


[1] "I don't really care if other people use it
    or not" - this sounds like... something
    that isn't my impression, that other people
    don't use it! Because almost _every_
    programmer I meet on the street and we
    start to talk about our stuff, they use
    some Unix system, most often Linux,
    sometimes BSD. "What editor do you use?"
    "Emacs." ~2/3 times. Only perhaps they can
    read my mind and give me the answer I so
    much desire... Wait! I just said I didn't
    care! What the heck am I talking about?!?


underground experts united

reply via email to

[Prev in Thread] Current Thread [Next in Thread]